Pathfinder Probe Transforms Red Planet Into the Whistling Planet

By WILLIAM J. BROAD

Published: November 10, 1998

Mars is windy. It has tattered clouds, dust storms, jet streams and dunes of windblown sand. In daytime, the sky can look salmon pink because of red dust in the air. In southern areas during the summer months, strong winds can occasionally stir up enough dust to cloak the entire planet. In general, fierce winds appear to have carved much of the Martian surface.

Now, for the first time, Earthlings are beginning to listen in to the winds, thanks to the Pathfinder probe that landed on Mars last year and recorded wind data that were later turned into sound. Another probe, Mars Polar Lander, set for launching in January and landing in December 1999, has on board a true microphone -- a first.

Until now, no sound of wind from any of the 70 or so planets and moons that make up the dissimilar worlds of the solar system has ever before been beamed back to Earth, scientists say. Many planetary bodies are roiled by atmospheric currents and disturbances and in theory can produce wind sounds that humans may one day hear.

As for Mars, its winds as revealed are intriguing and rich in texture. The sounds are similar to those of moody terrestrial blows.

The sounds arose not by design but because of a lecture given in Minnesota by Edward C. Stone, director of the Jet Propulsion Laboratory in Pasadena, Calif., which designed the Mars Pathfinder. At Gustavus Adolphus College in Minnesota, he gave a talk in October 1997, some three months after the sturdy little probe had landed on Mars and deployed its much-celebrated rover.

During the talk, Dr. Stone said the weather station of the main lander made wind measurements and suggested that in theory such data might be turned into sound.

He was later approached by Kelvin W. Miller, a public relations executive there, who asked if such a transformation could be tried. Dr. Stone subsequently approved the release to Mr. Miller of thousands of wind measurements taken on a Martian day in late July.

Mr. Miller worked with technically minded colleagues to transform the data into sounds that rise and fall in tone and volume, at times with whistling overtones suggestive of hard blows and dust devils. ''This is scientific, but it's also partly artistic,'' Mr. Miller said in an interview. ''It's probably more art than science.''

While listening to the Mars lecture, the music of Johann Sebastian Bach had come to mind, recalled Mr. Miller, a church musician. So early this year, with the extraterrestrial sounds in ear and hand, he worked with a pianist, Roderick Kettlewell, director of the Bach Society of Minnesota, to record a compact disk that weaves the sounds together with various Bach Preludes and other pieces by the composer.

Mr. Miller said the album, ''Winds of Mars'' (Music Crest Productions, Minneapolis), was his first recording. It was released last month and lists him as executive producer (www.windsofmars.com).

The window on Martian winds is expected to widen after the Mars polar craft makes its landing late next year and starts sending back sounds from its small microphone, which is akin to those in hearing aids.

The force behind this sound experiment was Carl Sagan, the astronomer, who died nearly two years ago. In 1996, he wrote to the National Aeronautics and Space Administration, arguing that ''public interest will be high and the opportunity for scientific exploration real'' if only a few minutes of Martian sound were obtained. Dr. Sagan was president of the Planetary Society, a private group in Pasadena, Calif., that backs space exploration.

After NASA approved the idea, the Planetary Society paid less than $100,000 for the microphone's development by a scientific team at the University of California at Berkeley. The microphone and its circuitry weigh about two ounces. The microphone is expected to record not only the sounds of wind but also blowing dust and perhaps electrical discharges in the Martian atmosphere crackling like lightning.

''This is going to be the first microphone to go to another planet,'' said Louis Friedman, the society's executive director. ''Who knows what it will hear?''

Photos: The windblown, dust-covered surface of Mars, as photographed by Pathfinder. (NASA); This new CD blends the sounds of Bach and the winds of Mars. (The New York Times)